In today's networked world, almost all network traffic travels on an optical fiber based network at one point or another. The volume of traffic continues to rise at a very rapid pace due to the fact that more devices are interconnected with one another and more applications deployed. Not only is the massive amount of traffic constantly created but also is its flow frequently changing as to the paths across an optical network. It presents a tremendous challenge to analysts who monitor the network for cyber security, and their abilities to take actions quickly to imminent threats. These threats are increasingly complex. They require a variety of processing and analytical tools to probe into the signals in parallel in real time. Current trends in bandwidth growth, protocol evolution, and multiple signal formats including DWDM make it more difficult to track and respond to events without significant increases in CAPEX and OPEX. There is a need for a flexible network platform to monitor and selectively intercept communications from geographically diverse areas, distribute the collected optical signals to one or multiple destinations, and centrally manage the process on demand from remote locations.
At the edge of this monitoring network, intelligent optical devices such as sensors, signal probes, data storage and other client devices are usually connected. Optical signals are selected and collected by devices at the ingress, and they are processed, analyzed, monitored and stored by client devices at the egress of the network. The optical signals collected by an ingress device have to be delivered faithfully to their final destination(s) or client(s) in their original analog forms without distortion. This requirement eliminates the use of Optical-Electronic-Optical (O-E-O) regeneration techniques employed by conventional digital communication fiber networks. The solution must leverage purely optical, photonic signal management techniques to create a ‘transparent’ path between end points of a network. This means that the network platform is independent of optical wavelengths, data formats or data rates. For example, it is capable of managing optical RF analog signals as well as digital signals such as 10G or 100G without the need for hardware or even software upgrades.
The basic components utilized by this all-optical distribution network include Optical Splitter, Optical Amplifier, and Wavelength Division Multiplexer (WDM), transparent Optical Cross-connect (OXC) or photonic switch and optical fibers interconnecting these components together with edge devices. An optical splitter is a passive device (no electrical power required) that splits the optical power carried by a single input fiber into multiple output fibers at a specified power ratio. An optical amplifier is a device that amplifies an optical signal directly, without the need to first convert it to an electrical signal. A Wavelength Division Multiplexer is also a passive device that separates or combines optical wavelengths. A transparent cross-connect is a device used to reconfigure optical signal paths in the network, which accepts optical signal without regard for its data rate or protocol. The reconfigurable fiber network constituted by these optical components, together with all intelligent end-devices connected at the edge of the network for signal collection, monitoring and analysis, provides an effective integrated and scalable network platform. It allows resource sharing, the flexibility and scalability to manage signal collection, distribution, remote monitoring as well as data storage for future growth in terms of optical capacity. In addition, this all-optical distribution network solution will dramatically reduce power consumption compared to electronic solution.
Photonic switch is the primary element to be managed that configures optical paths. Optical MEMS (Micro-Electro-Mechanical System) switch as an example of photonic switch, two of its micro-mirrors are physically manipulated and placed at angles that direct the optical signal beam, creating an optical cross-connect within the switch that ensures that the signal exits the switch via the desired port. Photonic switch-based Optical Signal Distribution Networks (OSDN), unlike electrical signal-based network devices, do not read or process the signal being distributed in order to determine a path for that signal in the same way electrical-based switches do. The control of photonic switch in a network is accomplished by either out-of-band or in-band method. Out-of-band method requires the management interface on an intelligent optical switch to be accessed via a separate network or connection from which the control instructions are received and processed by the switch to direct a received signal to an outgoing port. In-band method is that the control instructions are embedded in optical data channel and have to be separated from optical data when received by the switch prior to being processed.
The increased amount of network traffic traveling on optical networks and the ever changing traffic pattern flows have caused entities that analyze such traffic to build ad-hoc optical networks that are made up of many intelligent optical switches. These switches are interconnected with one another, and have various optical input signals. This type of ad hoc optical network is characterized by its temporary connections between edge devices. When a network operator wishes to perform data analysis on a particular input signal, that input signal is directed to a network edge device that has an output port connected to a data analysis system or probe that is capable of reading and analyzing the signal.
However, as these ad-hoc networks continue to grow, manually creating and configuring paths through these networks is becoming extremely difficult and time consuming. Furthermore, existing network management systems do not support path generation for photonic switches, as they rely on specific attributes of electric switches. Thus, there is an emerging need to build a flexible, expandable and transparent optical signal distribution network to connect an increasing number of optical signals to an ever expanding signal processing plant. The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section.